The Arena

At the start, pick your favorite Copy Ability and use the Warp Star to launch yourself to the main area. Here you have the option to grab one of the five Maxim Tomatoes or one of the two random Copy Abilities. You will return to this area after every boss fight.

After you complete both The Arena and the Dedede Tour at least once, you'll unlock the True Arena. This is the same mode, but all the bosses are now in their DX forms.